Information recording medium

ABSTRACT

A recording medium that is adapted to maximize the recording capacity and to simplify the configuration of an information recording/reproducing apparatus including a pickup. In the medium, a different type of wobbling signals are preformatted in each of the adjacent land and groove signal tracks. A same-phase wobbling signal provided by wobbling each side of the respective land and groove signal tracks in the same phase and a different-phase wobbling signal provided by wobbling each side of the respective land and groove signal tracks in a different phase are used as the different type of wobbling signals. The physical positions of all the land and groove signal tracks are indicated by the same-phase wobbling signal.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a recording medium having land andgroove tracks, and more particularly to a recording medium that isadapted to record information on both the land tracks and the groovetracks.

[0003] 2. Description of the Prior Art

[0004] Recently, an optical recording medium, an optical magneticrecording medium and so on have been developed as a recording medium forrecording various information such as video and audio information, etc.and are commercially available in the market. Such an optical recordingmedium includes a read-only type disc such as CD, CD-ROM, DVD-ROM, etc.,a write-once-read-many type disc such as CD-R, DVD-R, etc., and arewritable type disc such as CD-RW, DVD-RAM, etc.

[0005] In the conventional rewritable disc, it is previously recorded anidentified(hereinafter “ID”) information including an address (orposition) information allowing an information to be recorded in thedesired position. Actually, the optical disc such as CD-R, etc., asshown FIG. 1, includes a land and groove signal tracks 10 and 12 formedthereon. Also, the ID information including the address information,etc. is preformatted on the optical disc by wobbling the groove track 12in accordance with a carrier which the ID information isfrequency-modulated. The address information can be obtained from awobbling signal picked-up from the wobbled groove signal track 12 andthe information can be recorded at the desired position on the disc bythe obtained address information. In the optical disc having suchstructure, a recording capacity is limited because the information isrecorded on only the groove track 12.

[0006] Also, an optical disc such as DVD-R and so on, as shown FIG. 2,is known as the information can be recorded on all of land and groovesignal tracks 10 and 12. The optical disc comprises a header fieldhaving the ID information of address information, etc. recorded in apre-pit train and a recording field consisting of any one of the landand groove signal track 10 and 12 wobbled in the same phase. In thisdisc, since the information can be not recorded on the header fieldconsisting of the pre-pit train, the recording capacity is limited. Asdescribed above, the prior recording medium make to decrease an amountof information to be recorded on recordable area.

SUMMARY OF THE INVENTION

[0007] Accordingly, it is an object of the present invention to providea recording medium that is capable of increasing an amount of recordableinformation.

[0008] It is other object of the present invention to provide arecording medium that is capable of maximizing an amount of informationto be recorded on all of the land and groove signal tracks.

[0009] It is another object of the present invention to provide aninformation recording and reproducing apparatus that is capable ofperforming information record and reproduction for the above recordingmedium.

[0010] In order to achieve this and other objects of the invention, arecording medium according to an aspect of the present inventionincludes a signal track being wobbled in a predetermined frequency andhaving first and second wobbling areas. First wobbling area comprises areadable identified information, while second wobbling area has anon-readable identified information. Also, first and second wobblingareas is alternatively arranged.

[0011] An optical disc according to another aspect of the presentinvention includes a land track, a groove track alternated frequentlywith the land track, and a land/groove transition information includinga mirror pattern.

[0012] An apparatus for recording and reproducing an information on anoptical disc according to another aspect of the present inventionincludes: means for detecting a land/groove transition information onthe optical disc having a land and groove tracks alternated in apredetermined track period, the land/groove transition informationindicating a land/groove cross position between any one of the land andgroove tracks and the another track; and a servo motor unit, responsiveto the land/groove transition information, for controlling a servo motorand for inverting a tracking error signal in the polarity, the trackingerror signal forcing a light beam on the optical disc to be traced to acenter line of the land and groove tracks.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] This and other objects of the invention will be apparent from thefollowing detailed description of the embodiments of the presentinvention with reference to the accompanying drawings, in which:

[0014]FIG. 1 is a schematic view showing a signal track structure of aCD-R disc;

[0015]FIG. 2 is a schematic view showing a signal track structure of aDVD-RAM disc;

[0016]FIG. 3 is a schematic view showing a signal track structure of anoptical disc according to an embodiment of the present invention;

[0017]FIG. 4 is a schematic view showing a signal track structure of atwo-spiral type optical disc according to an embodiment of the presentinvention;

[0018]FIG. 5 is a schematic view showing a signal track structure of aone-spiral type optical disc according to an embodiment of the presentinvention;

[0019]FIG. 6 is a view for explaining a changing state in frame IDspreformatted in signal tracks of the optical disc shown in FIG. 4;

[0020]FIG. 7 is a view for explaining a changing state in frame IDspreformatted in signal tracks of the optical disc shown in FIG. 5;

[0021]FIG. 8 is a schematic view showing a signal track structure of anoptical disc according to another embodiment of the present invention;

[0022]FIG. 9 illustrates wobbling signals detected from the optical dischaving the signal track structure in FIG. 9 and synchronous patterns andidentification codes decoded with the wobbling signals;

[0023]FIG. 10 is a schematic view showing a conventional informationrecording/reproducing apparatus for accessing an optical disc having thesignal track structure in FIG. 1 or FIG. 2;

[0024]FIG. 11 is a detailed view of the photo detector shown in FIG. 10.

[0025]FIG. 12 is a detail view of the frame identification code patternon the same-phase wobbling area 34A as shown in FIG. 8;

[0026]FIG. 13 is a schematic view showing a signal track structure of anoptical disc according to still another embodiment of the presentinvention;

[0027]FIGS. 14A and 14B are detail view of the land/groove transitioninformation as shown in FIG. 13;

[0028]FIG. 15 is a schematic view showing an optical discrecording/reproducing apparatus for accessing an optical disc having thesignal track structure in FIG. 12 or FIG. 13, according to an embodimentof the present invention;

[0029]FIG. 16 is a schematic view showing a signal track structure of anoptical disc according to still another embodiment of the presentinvention;

[0030]FIG. 17A is a detail view of the land/groove transitioninformation preformatted on the land/groove cross portion as shown inFIG. 16;

[0031]FIG. 17B is a detail view of the transition data pattern includedin the land/groove transition information as shown in FIG. 17A;

[0032]FIG. 18 is a schematic view showing an optical discrecording/reproducing apparatus for accessing an optical disc having thesignal track structure in FIG. 16, according to an embodiment of thepresent invention;

[0033]FIG. 19 is a detail block diagram of the land/groove transitioninformation detector 96 as shown in FIG. 18; and

[0034]FIG. 20 is a waveform diagram showing signals generated in eachthe circuitry element shown in FIG. 19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] Referring to FIG. 3, there is shown an optical disc according toan embodiment of the present invention having land and groove signaltracks 20 and 22. The land and groove signal tracks 20 and 22 aredefined in parallel in a spiral pattern from the innermost circumferenceto the outermost circumference of the optical disc as shown in FIG. 4,or arranged alternately every rotation period from the innermostcircumference to the outermost circumference in such a manner to formone spiral signal track as shown in FIG. 5. Each of land and groovesignal tracks 20 and 22 includes same-phase wobbling areas 24A anddifferent-phase wobbling areas 24B that intersect at every predeterminedregion and appear alternately in the circumference direction i.e., theproceeding direction of the respective track. These same-phase wobblingareas 24A alternate with the difference-phase wobbling areas 24B in thediameter direction i.e., the width direction of the land and groovetrack 20 and 22. In the same-phase wobbling area 24A represented by theoblique lines in FIG. 3, being preformatted with ID informationincluding an address information, etc. thereon, each side of therespective land and groove signal tracks 20 and 22 is wobbled to havethe same-phase in accordance with carrier which ID information isfrequency-modulated. Each side of the difference-phase wobbling areas24B is wobbled to have the difference phase by alternating thedifference-phase wobbling areas 24B with the same-phase wobbling areas24A in both the proceeding direction and the width direction of thesignal tracks 20 and 22. As a result, the address information can beobtained from a wobbling signal on only same-phase wobbling area 24A.For example, if a pair of the same-phase area 24A and thedifference-phase wobbling area 24B is used for an information recordingunit i.e., one frame as shown FIG. 3, the address information is readoutfrom only the same-phase wobbling area 24A positioned in front and backof the difference-phase wobbling area 24B so that an user information isrecorded in the information recording unit on the basis of the readoutaddress information. Therefore, in the recording medium having suchstructure, the information can be recorded on all of the land and groovesignal tracks 20 and 22, furthermore all of recordable areas is used.

[0036]FIG. 4 shows an optical disc, wherein the land and groove tracks20 and 22 as shown in FIG. 3 are defined in parallel in a spiral shape.In the diameter direction, the same-phase wobbling area 24A ispositioned in only the land signal track 20 or the groove signal track22 and the different-phase wobbling area 24B is positioned in only thegroove signal track 22 or the land signal track 20. In other words, thesame-phase wobbling area 24A and the different-phase wobbling area 24Bappear alternately in both the circumference direction and the diameterdirection. j same-phase wobbling areas 24A and j different-phasewobbling areas 24B are alternately arranged in each of the land andgroove signal tracks 20 and 22 for one turn to divide the signal track20 and 22 for one turn into j frames. As shown in FIG. 6, the same-phasewobbling areas 24A formed in the land signal track 20 have sequentiallyincreasing frame identification codes PIDs, respectively. Likewise, thesame-phase wobbling areas 24A formed in the groove track 22 also havesequentially increasing frame identification codes PIDs, respectively.

[0037]FIG. 5 shows an optical disc, wherein the ID information of theaddress information, etc. is preformatted on each of the land and groovetracks 20 and 22 which is alternated by one turn to make single spiralshape, as shown in FIG. 4. In FIG. 5, the single signal track is changedfrom the land signal track 20 to the groove signal track 22 or from thegroove signal track 22 to the land signal track 20 on the basis of aland/groove cross line. Also, the same-phase wobbling area 24A and thedifference-phase wobbling area 24B are alternatively arranged in each ofthe land and groove signal tracks 20 and 22. In the diameter, thesame-phase wobbling area 24A is positioned in only the land signal track20 or the groove signal track 22 and the different-phase wobbling area24B is positioned in only the groove signal track 22 or the land signaltrack 20. That is, the same-phase wobbling area 24A and thedifferent-phase wobbling area 24B appear alternately in both thecircumference direction and the diameter direction. In order toalternate the same-phase wobbling area 24A and the difference-phasewobbling area 24B in the diameter direction, the same-phase wobblingareas 24A and the difference-phase wobbling areas 24B included in eachof the signal tracks 20 and 22 for one turn is increased by one in thenumber as the signal tracks 20 and 22 are proceeded from innercircumference to outer circumference. For example, in the signal tracks20 and 22 for two turns (i.e., a pair of land and groove signal tracks20 and 22), 2m+1 same-phase wobbling areas 24A and 2m+1 difference-phasewobbling areas exist. That is, 2m+1 frames exist. Therefore, in thesignal track 20 or 22 for one turn, any one area of both areas is m+1and the other area is m. Furthermore, if the signal tracks 20 and 22 fortwo turns (i.e., a pair of land and groove signal tracks 20 and 22) aredivided into 7 frames, m is 3 and so the same-phase wobbling area 24Aand the difference-phase wobbling area 24B exist by 7, respectively. Indetail, 4(=m+1) same-phase wobbling areas 24A and 3(=m) difference-phasewobbling areas 24B are arranged in the signal track for first one turn(i.e., in the land signal track 20) and 3(=m) same-phase wobbling areas24A and 4(=m+1) difference-phase wobbling areas 24B are positioned inthe signal track for second one turn (i.e., in the groove signal track22).

[0038] Referring now to FIG. 8, there is shown an optical disc accordingto another embodiment of the present invention having land and groovesignal tracks 30 and 32. The optical disc of FIG. 8 includes thesame-phase wobbling area 34A and difference-phase wobbling area 34B suchas in FIG. 3 and further comprises a pre-wobbling area 34C andpost-wobbling area 34D which a synchronous pattern is preformatted ineach front of the same-phase wobbling area 34A and the differencewobbling area 34B. The pre-wobbling area 34C and post-wobbling area 34Dare formed on both the land and groove signal tracks 30 and 32 in sameformat. That is, the pre-wobbling area 34C and the post-wobbling area34D have the same phase without regarding to the land and groove signaltracks 30 and 32. Also, in each of the pre-wobbling area 34C andpost-wobbling area 34D, the different synchronous patterns each other,i.e. logical values having a complementary relationship are respectivelypreformatted. Since the land and groove tracks 30 and 32 have opticalcharacteristics contrary to each other and the pre-wobbling area 34C andpost-wobbling area 34D are alternatively arranged in the width directionof the signal tracks 30 and 32, signals having phases contrary to eachother are detected from each of the pre-wobbling area 34C and thepost-wobbling area 34D having the same phase. In detail, the synchronouspatterns preformatted on the pre-wobbling areas 34C represented byoblique lines in FIG. 8 have the same logical value, likewise thesynchronous patterns preformatted on post-wobbling areas 34D representednot by oblique lines also have the same logical value. Contrarily, thesynchronous patterns on the pre-wobbling area 34C represented by theoblique lines and on the post-wobbling area 34D represented not by theoblique lines have logical values in the complementary relationship,respectively. The synchronous patterns preformatted on the pre-wobblingarea 34C and on the post-wobbling area 34D indicate reference points foreach of the same-phase wobbling area and the difference-phase wobblingarea 34D.

[0039]FIG. 9 illustrates the synchronous patterns detected from thepre-wobbling area 34C and the post-wobbling area 34D as shown in FIG. 8.A pre-synchronous pattern is detected from the pre-wobbling area 34C anda post-synchronous pattern is obtained from the post-wobbling area 34D.A LWS is a wobbling signal detected from the land signal track 30 and aGWS is a wobbling signal detected from the groove signal track 32. Thesewobbling signals LWS and GWS include a pre-synchronous componentdetected from the pre-wobbling area 34C and a post-synchronous componentdetected from the post-wobbling area 34D, wherein the pre-synchronouscomponent and the post-synchronous component have the phases contrary toeach other, respectively. The pre-synchronous pattern of “00010111” andthe post-synchronous pattern of “11101000” are obtained by demodulatingthe pre-synchronous component and post-synchronous component. In otherwords, the pre-synchronous pattern and the post-synchronous pattern arereadout from each of the land and groove signal tracks 30 and 32adjacent to each other. These synchronous patterns is preformatted onthe signal tracks 30 and 32 so that it is effectively performed theaccess of the optical disc.

[0040] Referring now to FIG. 10, there is shown a conventionalinformation recording/reproducing apparatus for accessing the opticaldisc in FIG. 1 and FIG. 2. A process of accessing the optical discsaccording to embodiments of the present invention using this informationrecording/reproducing apparatus will be explained below. In FIG. 10, theinformation recording/reproducing apparatus includes a spindle motor 42for rotating an optical disc 40, an optical pickup 44 for accessing theoptical disc 40 and a signal detector 46 connected, in series, to theoptical pickup 44. The optical pickup 44 irradiates a light beam ontoland or groove signal tracks of the optical disc 40, that is, onto theland or groove signal tracks 20 or 22 as shown in FIG. 3, or the land orgroove signal tracks 30 or 32 as shown in FIG. 8, thereby writing aninformation into the land or groove signal tracks, or reading out theinformation written into the land or groove signal tracks. To this end,the optical pickup 44 includes a beam splitter BS for guiding a lightbeam from a laser diode LD to an objective lens OL and a light beam fromthe objective lens LD to a photo detector PD, and an actuator AC formoving the objective lens to the up, down, left, and right to perform afocusing and a tracking. The objective lens OL converges a light beamdirecting the beam splitter BS to the optical disc 40. The beam splitterBS allows a light beam from the laser diode LD to be irradiated, via theobjective lens OL, onto the land signal track or the groove signal trackof the optical disc 40, and allows a light beam reflected by the opticaldisc 40 to be progressed to the photo detector PD. The actuator AC movesthe objective lens OL in the up and down direction, thereby irradiatinga light beam onto the surface of the land or groove signal track in aspot shape. Also, the actuator AC moves the objective lens OL in theleft and right direction, thereby tracing a light beam along the centerline of the land or groove track. The photo detector PD converts aquantity of the reflective light received, via the objective lens OL andthe beam splitter BS, from the optical disc 40 into an electricalsignal. As shown in FIG. 11, the photo detector PD consists of fourphoto detecting pieces PDa to PDd so that it can detect a distributionof the light irradiated onto the signal tracks 20 and 22. The four lightdetecting pieces PDa to PDd are positioned such that they correspond toeach other for two pieces on a basis of the progressing direction of thesignal track. In other words, the first and fourth light detectingpieces PDa and PDd are positioned at the outer circumference or theinner circumference on the basis of the progress direction of the signaltrack; while the second and third light detecting pieces PDb and PDc arepositioned at the inner circumference or the outer circumference,respectively. The signal detector 46 detects a wobbling signal W, afocusing error signal Fe, a tracking error signal Te and a radiofrequency signal RF included in first to fourth electrical signals Pa toPd. The wobbling signal W, the focusing signal Fe, the tracking errorsignal Te and the radio frequency signal RF are obtained by calculatingthe first to fourth electrical signals Pa to Pd by the followingequations:

W=(Pa+Pd)−(Pb+Pc)  (1)

Fe=(Pa+Pc)−(Pb+Pd)  (2)

Te=∫[(Pa+Pd)−(Pb+Pc)]dt  (3)

RF=Pa+Pb+Pc+Pd  (4)

[0041] When an optical disc shown in FIG. 3 is recorded or reproduced,the wobbling signal W includes a same-phase wobbling component detectedfrom a region in which each side of the land or groove track 20 or 22 iswobbled in the same phase, and a different-phase wobbling componentdetected from a region in which each side of the land or groove track 20or 22 is wobbled in a different phase. Otherwise, when an optical discshown in FIG. 8 is recorded or reproduced, the wobbling signal Wincludes a same-phase wobbling component detected from a region in whicheach side of the land or groove track 30 or 32 is wobbled in the samephase, a different-phase wobbling component detected from a region inwhich each side of the land or groove track 30 or 32 is wobbled in thedifferent phase, and a pre-wobbling and post-wobbling componentsdetected from each of the pre-wobbling area 34C and post-wobbling area34D in which each side of the land and groove signal tracks 30 and 32 iswobbled in the same phase.

[0042] A focusing servo 68 included in the informationrecording/reproducing apparatus responds to the focusing error signal Fefrom the signal detector 66 to control a voltage or a current suppliedto the actuator Ac, thereby moving the objective lens OL in the verticaldirection by means of the actuator Ac. By moving the objective lens OLin the vertical direction, a spot-shaped light beam is irradiated ontothe land or groove track of the optical disc 60. Likewise, a trackingservo 70 responds to the tracking error signal Te to control a voltageor a current supplied to the actuator Ac, thereby moving the objectivelens OL in the horizontal direction by means of the actuator Ac. Bymoving the objective lens OL in the horizontal direction, a light beamirradiated onto the optical disc 40 traces the land or groove track.

[0043] The information recording/reproducing apparatus includes areproducing information processor 52 receiving the radio frequencysignal RF from the signal detector 46, and a recordingclock/identification code detector 54 receiving the wobbling signal Wfrom the signal detector 46. The reproducing information processor 52detects a channel bit stream from the radio frequency signal RF anddecodes the channel bit stream, thereby reproducing an informationrecorded on the land or groove signal track 20 or 22 shown in FIG. 3, orrecorded on the land or groove signal track 30 or 32 shown in FIG. 8.The information generated in the reproducing information processor 42 isoutput to an output line 41. Meanwhile, the recordingclock/identification code detector 44 detects a recording clock SCLK, anidentification code ID including an address, etc. indicating thephysical position of the frame, and a rotation speed informationindicating a rotation speed of the optical disc 40. When the opticaldisc 40, in which the same-phase and different-phase wobbling area 24Aand 24B are formed as shown in FIG. 3, is recorded or reproduced, orwhen the optical disc 40, in which the same-phase and different-phasewobbling area 34A and 34B and pre-wobbling and post-wobbling signals 34Cand 34D are formed as shown in FIG. 8, is recorded or reproduced, therecording clock/identification code detector 74 detects the recordingclock SCLK, the identification code ID and the rotation speedinformation from the same-phase component included in the wobblingsignal W and the pre-synchronous and post-synchronous patterns from eachof the pre-wobbling and post-synchronous components. Otherwise, when adifferent-phase wobbling component is input, the recordingclock/identification code detector 54 indicates the generation of error.Meanwhile, the recording information processor 56 makes a blocking of arecording information input from the input line 43 into a frame size andadds the identification code ID to each blocked information, therebyproducing a channel bit stream. Further, the recording informationprocessor 56 transfers the channel bit stream to a light controller 58in conformity to the recording clock SCLK from the recordingclock/identification code detector 54. Then, the light controller 58intermits a light beam generated at the laser diode LD in accordancewith a logical value of the channel bit stream from the recordinginformation processor 76, thereby recording the channel bit stream onthe signal track of the optical disc 40, i.e., the land or groove signaltrack 20 or 22 in FIG. 3, or the land or groove signal track 30 or 32 inFIG. 8.

[0044] The information recording/reproducing apparatus includes arotation control signal generator 60 and a motor driver 62 that areconnected, in series, between the recording clock/identification codedetector 54 and the spindle motor 42, and a controller 64 forcontrolling a recording/reproducing operation. The rotation controlsignal generator 60 detects a rotation speed error amount from therotation speed information from the recording clock/identification codedetector 54 and controls a voltage level or a current amount of therotation control signal applied to the motor driver 62 in accordancewith the detected rotation speed error amount. Then, the motor driver 62accelerates or decelerates the rotation speed of the spindle motor 42 inaccordance with a voltage level or a current amount of the rotationspeed signal from the rotation speed signal generator 60. Byaccelerating or decelerating the rotation speed of the spindle motor 42,a play speed in the signal track of the optical disc 40 is maintainedconstantly. The controller 64 controls the operation state of thefocusing servo 48 and the tracking servo 50. Also, the controller 64operates the recording information processor 56 and the reproducinginformation processor 52 selectively in a recording/reproducing mode andcontrol the light controller 58 in accordance with therecording/reproducing mode, thereby controlling an intensity of a lightbeam generated at the laser diode LD.

[0045]FIG. 12 explains a frame identification code pattern on thesame-phase wobbling area 34A as shown in FIG. 8. The frameidentification code pattern is positioned between the pre-synchronouspattern and post-synchronous pattern and indicates a frame arearecording a user information of frame. The frame identification codepattern includes a frame information FI of 1 byte, a physical addressPID of 3 bytes and an error detecting code EDC of 2 bytes. The frameinformation indicates whether the frame identification code pattern ispre-formatted at any one of the land and groove signal tracks 30 and 32.A most significant bit FIb7 included in the frame information FIrepresents whether the frame information FI is valid or not. A secondlyhigher significant bit FIb6 next the most significant bit FIb7 indicateswhether the frame identification code pattern is pre-formatted on anyone of the land and groove signal tracks 30 and 32. The rest 6 bits FIb5to FIb0 have an information for a transition between the land and groovesignal tracks 30 and 32, for example the number of frame identificationcode patterns from the corresponding frame identification code patternto a transition between the land and groove signal tracks. If the mostsignificant bit FIb7 is “1” and the secondly higher significant bit FIb6is “1” (or “0”), the frame identification code pattern (i.e., the frameinformation FI) indicates the track identifying information, the numberof other frame identification code patterns from the corresponding frameidentification code pattern to the transition position between the landand groove signal tracks 30 and 32, and a fact of that the correspondingframe identification code pattern is recorded on the land signal track30 or on the groove signal track 32.

[0046] Also, the frame information FI can be used to record anotherinformation. For example, the frame information includes otherinformation when the its most significant bit FIb7 is “0”. Such a frameinformation can be included in each frame identification code pattern orrecorded every a predetermined frame identification code patterns.

[0047] An optical disc reproducing apparatus detects the frameinformation FI of the frame identification code pattern on the disc andreads out a logical value of the frame information FI, therebydetermining whether any one of the land and groove signal tracks 20 and22 is accessed now. Also, the optical disc reproducing apparatus findsout the transition position between the land and groove signal tracks 20and 22.

[0048] In the frame identification code pattern, the physical addressPID between the frame information FI and the error detecting code EDCindicates a position on the disc in which a user data is recorded. Theerror detecting code EDC represents whether errors are in the frameinformation FI and the physical address PID or not. Also, the errordetecting code EDC is used to correct the errors in the frameinformation FI and the physical address PID. To this end, the errordetecting code EDC can be recorded on the disc in a CRC (CyclicRedundancy Check) code.

[0049]FIG. 13 illustrates a disc of land/groove recording systemaccording to an embodiment of the present invention, which has asynchronous pattern or signal allowing the transition position on thedisc to be detected.

[0050] Referring to FIG. 13, the disc according to an embodiment of thepresent invention includes same-phase wobbling areas 34A anddifferent-phase wobbling areas 34B arranged alternatively betweensynchronous patterns (or signals) 34C and 34D, on each land and groovesignal track 30 and 32. Also, the disc comprises another synchronouspatterns 34CT and 34DT for indicating the transition position betweenthe land and groove signal tracks 30 and 32. On the basis of a physicaladdress preformatted on the same-phase wobbling area 34A in a shapewhich both side of the signal track 30 or 32 is wobbled, a user data isrecorded on the same-phase wobbling area 34A and the different-phasewobbling area 34B. The synchronous pattern 34C and 34D is preformattedbetween the same-phase wobbling area 34A and the different-phasewobbling area 34B and defines the same-phase wobbling area 34A and thedifferent-phase wobbling area 34B. The another synchronous pattern (orsignal) 34CT and 34DT is preformatted at a position adjacent to aland/groove cross line and has a data being against a bi-phasemodulating regulation, thereby indicating the transition positionbetween the same-phase wobbling area 34A and the different-phasewobbling area 34B. In other words, the present invention allows apre-synchronous pattern 34CT and post-synchronous pattern 34DT of thesame-phase wobbling area 34A at each starting portion of the land orgroove signal track 30 or 32 to have the data being against the bi-phasemodulating regulation, thereby indicating the transition positionbetween the same-phase and different-phase wobbling areas 34A and 34B.For example, the pre-synchronous pattern 34CT or post-synchronouspattern 34DT of the same-phase wobbling area 34A at each startingportion of the land or groove signal track 30 or 32 are preformatted tohave the data (or code) such as “11111111” or “00000000” which bitshaving a identified value are continued to be against the bi-phasemodulating regulation, as shown in FIGS. 14A and 14B.

[0051]FIG. 15 shows an optical recording/reproducing apparatus accordingto an embodiment of the present invention. The opticalrecording/reproducing apparatus accesses the optical disc shown in FIGS.12, 13, 14A and 14B.

[0052] The optical recording/reproducing apparatus of FIG. 15 has aconfiguration similar to the information recording/reproducing apparatusshown in FIG. 11. The difference between the opticalrecording/reproducing apparatus of FIG. 15 and the informationrecording/reproducing apparatus of FIG. 10 is that the opticalrecording/reproducing apparatus further includes a land/groovedeterminer 66 receiving a land/groove track transition information fromthe recording clock/identification code detector 54 and a polarityinverter 68 connected among the signal detector 46, the tracking servo50 and the land/groove determiner 66.

[0053] The optical pickup 44 irradiates a light beam onto land or groovesignal tracks of the optical disc 40, that is, onto the land or groovesignal tracks 30 or 32 as shown in FIG. 13, thereby writing aninformation into the land or groove signal tracks. Also, the opticalpickup 44 converts the lights reflected by the disc 40 into anelectrical signal and reads out the information written into the land orgroove signal tracks. The signal detector 46 detects a wobbling signalW, a focusing error signal Fe, a tracking error signal Te, and a radiofrequency signal RF included in four electrical signals from fourdetecting pieces of the optical pickup 44. The recordingclock/identification code detector 54 receives the wobbling signal W anddetects the land/groove transition information, a recording clock SCLK,an identification code ID including an address, etc. indicating thephysical position of the frame, and a rotation speed informationindicating a rotation speed of the optical disc 40. If the disc 40 hasthe frame information FI of 1 byte preformatted between the synchronouspattern (or signal) 34C and the physical address PID as shown FIG. 12,the recording clock/identification detector 54 detects the frameinformation FI from the wobbling signal W and generates the land/groovetrack transition information on the basis of the frame information FI.On the other hand, when the optical disc 40 includes the land/groovetrack transition information preformatted at the pre-synchronous pattern34CT or post-synchronous pattern 34DT of the same-phase wobbling area34A in the starting and end portions of the land or groove signal track30 or 32, the recording clock/identification detector 54 detects thecorresponding synchronous pattern (or signal) from the wobbling signal Wso as to generates the land/groove track transition information.

[0054] The reproducing information processor 52 detects a channel bitstream from the radio frequency signal RF and decodes the channel bitstream, thereby reproducing an information recorded on the land orgroove signal track 20 or 22 shown in FIG. 3, or recorded on the land orgroove signal track 30 or 32 shown in FIG. 8. The recording informationprocessor 56 makes a blocking of a recording information (or a userdata) input from the input line 43 into a frame size and adds theidentification code ID, which is received from the recordingclock/identification detector 54 to each blocked information, therebyproducing a channel bit stream. Further, the recording informationprocessor 56 transfers the channel bit stream to a light controller 58in conformity to the recording clock SCLK from the recordingclock/identification code detector 54. Then, the light controller 58intermits a light beam generated at the laser diode LD in accordancewith a logical value of the channel bit stream from the recordinginformation processor 56, thereby recording the channel bit stream onthe signal track of the optical disc 40, i.e., the land or groove signaltrack 20 or 22 in FIG. 3, or the land or groove signal track 30 or 32 inFIG. 8.

[0055] The land/groove determiner 66 controls the polarity inverter 58in accordance with the land/groove track transition information from therecording clock/identification detector 54. The polarity inverter 68inverts a polarity of the tracking error signal to be transferred fromthe signal detector 46 to the tracking servo 50 upon a control of theland/groove determiner 66, at each time which the land/groove tracktransition information L/G is generated, i.e., every a predeterminedtrack period which the signal track changes from the land signal trackor the groove signal track to the groove signal track or the land signaltrack.

[0056] The tracking servo 50 responds to the tracking error signal Tefrom the polarity inverter 68 to control a voltage or a current suppliedto the actuator Ac, thereby moving the objective lens OL in thehorizontal direction by means of the actuator Ac. By moving theobjective lens OL in the horizontal direction, a light beam irradiatedonto the optical disc 40 traces the land or groove track. Likewise, thefocusing servo 48 responds to the focusing error signal Fe from thesignal detector 46 to control a voltage or a current supplied to theactuator Ac, thereby moving the objective lens OL in the verticaldirection by means of the actuator Ac. By moving the objective lens OLin the vertical direction, a spot-shaped light beam is irradiated ontothe land or groove track of the optical disc 40.

[0057] The rotation control signal generator 60 detects a rotation speederror amount from the rotation speed information from the recordingclock/identification code detector 54 and controls a voltage level or acurrent amount of the rotation control signal applied to the motordriver 62 in accordance with the detected rotation speed error amount.Then, the motor driver 62 accelerates or decelerates the rotation speedof the spindle motor 42 in accordance with a voltage level or a currentamount of the rotation speed signal from the rotation speed signalgenerator 60. By accelerating or decelerating the rotation speed of thespindle motor 42, a play speed in the signal track of the optical disc40 is maintained constantly. The controller 64 controls the operationstate of the focusing servo 48 and the tracking servo 50. Also, thecontroller 64 operates the recording information processor 56 and thereproducing information processor 52 selectively in arecording/reproducing mode and control the light controller 58 inaccordance with the recording/reproducing mode, thereby controlling anintensity of a light beam generated at the laser diode LD.

[0058]FIG. 16 illustrates an optical disc according to still anotherembodiment of the present invention.

[0059] Referring to FIG. 16, the optical disc includes same-phase areas74A and different-phase areas 74B arranged alternately on each of landand groove signal tracks 70 and 72, and a land/groove cross portion 76that the track changes from the land signal track 70 to the groovesignal track 72 or from the groove signal track 72 to the land signaltrack 70. On the land/groove cross portion 76, there is recorded aland/groove transition information for indicating a transition positionbetween the land and groove signal tracks 70 and 72. The land/groovetransition information enables the land/groove cross portion 76 to bedetected. Therefore, an inversion of a tracking error signal, a controlcondition and so on can be varied.

[0060]FIG. 17A explains the land/groove transition information recordedon the land/groove cross portion 76 of the optical disc.

[0061] In FIG. 17A, the land/groove transition information includesfirst and second mirror patterns (or regions) 80A and 80B arranged in aproceeding direction of each signal track 70 and 72, and a transitiondata pattern (region) 82 between the first and second mirror patterns80A and 80B. Each mirror patterns 80A and 80B positioned at both end ofthe transition data pattern 82 is formed in a predetermined size (forexample, 4 bytes). The transition data pattern 82 includes spacers 84and recording marks 86 arranged alternately by the predetermined number(for example, by each 75), as shown in FIG. 17B. The spacer 84 has thesize of 4T and the recording mark 86 is formed in the size of 4T. Thenumber of the spacers 84 and the recording marks 86 can be adjusted by amanufacturer. Therefore, the optical disc recording/reproducingapparatus can detects the land/groove cross portion 76 on the basis ofthe mirror patterns 80A and 80B and the transition data pattern 82.

[0062]FIG. 18 shows an optical disc recording/reproducing apparatusaccording to another embodiment of the present invention.

[0063] In FIG. 18, the optical disc recording/reproducing apparatusincludes a signal detector 90 for detecting a radio frequency signal RFand a push-pull signal PP from an optical disc, a radio frequency signalprocessor 92 for compensating the radio frequency signal RF from thesignal detector 90, a modulator/demodulator 94 for modulating anddemodulating the radio frequency signal RF from the radio frequencysignal processor 92, a land/groove transition information detector 96for detecting the land/groove cross portion 76 on the optical disc, anda servo 98 for extracting various signals from the push-pull signal PPand for driving an actuator. The signal detector 90 detects the radiofrequency signal RF and the push-pull signal PP from the optical disc.The push-pull signal PP detected by the signal detector 90 is applied tothe servo 98. The servo 98 detects a tracking error signal included inthe push-pull signal PP and drives the actuator on the basis of thedetected tracking error signal, thereby allowing a light beam convergedon the optical disc to tracing the center line of the land or groovesignal track 70 or 72.

[0064] Meanwhile, the radio frequency signal RF detected in the signaldetector 90 is supplied to the radio frequency signal processor 92 andthe land/groove transition information detector 96. The radio frequencysignal processor 92 compensates the radio frequency signal RF from thesignal detector 92 so that the radio frequency signal RF can be recordedand reproduced. The compensated radio frequency signal from the radiofrequency signal processor 92 is applied to the modulator/demodulator94. The modulator/demodulator 94 modulates or demodulates thecompensated radio frequency signal from the radio frequency signalprocessor 92. The radio frequency signal RF modulated in themodulator/demodulator 94 is recorded on the optical disc through arecording unit (not shown). The radio frequency signal RF demodulated inthe modulator/demodulator 94 is reproduced by means of a reproducingunit (not shown).

[0065] Also, the land/groove transition information detector 96 detectsthe land/groove transition information, thereby determining whether thelight beam arrives at the land/groove cross portion 76. The land/groovetransition information detector 96 applies a switching signal TS, aconfirmative signal CF and a masking signal MS to the servo 98 when theland/groove transition information is detected. The servo 98 inverts apolarity of the tracking error signal and changes a control status ofthe servo motor, at each time which the switching signal is received.The servo 98 responds to the comfirmative signal CF and maintains theswitched control status and the polarity of the tracking error signal.On the other hand, the servo 98 returns to the original status when theconfirmative signal CF is not received until the end time (or fallingedge) of the masking signal MS (i.e., the falling edge of the secondmirror pattern 80B).

[0066]FIG. 19 illustrates in detail the land/groove transitioninformation detector 96 as shown in FIG. 18.

[0067] Referring to FIG. 19, the land/groove transition informationdetector 96 includes a mirror pattern (or region) detector 100 fordetecting the first and second mirror patterns 80A and 80B included inthe radio frequency signal from the signal detector 90 shown in FIG. 18,a 4T signal detector 102 for detecting spacers of 4T and recording marksof 4T of transition data pattern 82 included in the radio frequencysignal RF from the signal detector 90 of FIG. 18, first and secondcounters 104 and 106 for counting the number of the spacers andrecording marks, and a masking signal generator 108 for generating amasking signal MS. The operation of such a land/groove transitioninformation detector 96 will be described in reference to FIG. 20.

[0068] The mirror pattern detector 100 receiving the radio frequencysignal RF from the signal detector 90 in FIG. 18 detects the first andsecond mirror patterns 80A and 80B recorded in the land/groove crossportion 76 of the optical disc. At each time which the mirror patternBOA or SOB recorded in the land/groove cross portion 76 of the opticaldisc is detected, the mirror pattern detector 100 generates a mirrorpattern detecting signal having a pulse of constant width. In otherwords, the mirror pattern detector 100 generates a first mirror patterndetecting signal responsive to the first mirror pattern 80A and a secondmirror pattern detecting signal responsive to the second mirror pattern80B. Consequently, the mirror pattern detecting signal MD generated inthe mirror pattern detector 100 has a waveform as shown in FIG. 20. Themirror pattern detecting signal MD is applied to the masking signalgenerator 108 and the first counter 104.

[0069] The masking signal generator 108 responds to the mirror patterndetecting signal MD to generates the masking signal MS as shown in FIG.20. The masking signal MS has a pulse which maintains a first logiclevel during the period proceeding from a starting point (i.e., a risingedge) of the first mirror pattern 80A to an end point (i.e., a fallingedge) of the second mirror pattern 80B. In other words, the maskingsignal changes to the first logic level or value (for example, a highlogic level) when the first mirror pattern 80A is detected. The maskingsignal is transited from the first logic level to a second logic levelor value (for example, a low logic level) when the second mirror pattern80B is detected. The masking signal MS generated in the masking signalgenerator 108 is applied to the 4T signal detector 102 and the first andsecond counters 104 and 106. The masking signal MS also is supplied tothe servo 98 shown in FIG. 18.

[0070] The 4T signal detector 102 detects the spacer 84 of 4T and therecording mark 86 of 4T included in the radio frequency signal RF fromthe signal detector 90 of FIG. 18 when the masking signal MS from themasking signal generator 108 is received. In other words, the 4T signaldetector 102 performs the detecting operation of the spacer andrecording mark while the masking signal MS maintains the specific logiclevel (i.e., the high logic level). The 4T signal detector 102 generatesa 4T pulse signal (not shown) at each time which the spacer of 4T andthe recording mark of 4T are detected. The 4T pulse signal generated inthe 4T signal detector 102 is applied to the first and second counters104 and 106.

[0071] The first counter 104 performs a counting operation of the 4Tpulse signal during the interval of the first logic level (i.e., thehigh logic level) of the masking signal MS. The first counter 104 startsthe counting operation of the 4T pulse signal at the starting point (forexample, the raising edge) of the mirror pattern detecting signal MD. Inother words, the first counter 104 starts the counter operation of the4T pulse signal when the first mirror pattern 80A is detected. In thecounting operation, the first counter 104 counts the 4T pulse signalreceived from the 4T signal detector 102 and generates the switchingsignal TS of pulse shape as shown in FIG. 20 when a counted valuearrives at a first predetermined value (for example, 50). The switchingsignal TS generated in the first counter 104 is applied to the secondcounter 106 and the servo 98 shown in FIG. 18. The servo 98 responds tothe switching signal TS from the first counter 104 and inverts thepolarity of the tracking error signal.

[0072] The second counter 106 performs the counting operation of the 4Tpulse signal during the interval of the first logic level (i.e., thehigh logic level) of the masking signal MS. The second counter 106starts the counting operation of the 4T pulse signal at the startingpoint (for example, the raising edge) of the switching signal TS. In thecounting operation, the second counter 106 counts the 4T pulse signalreceived from the 4T signal detector 102 and generates a comfirmativesignal CF of pulse shape as shown in FIG. 20 when a counted valuearrives at a second predetermined value (for example, 100). Theconfirmative signal CF generated in the second counter 106 is applied tothe masking signal generator 108 and the servo 98 shown in FIG. 18. Theservo 98 responds to the comfirmative signal CF and maintains a switchedstatus. Meanwhile, the servo 98 returns to the original status when theconfirmative signal CF is not received until the end time (or fallingedge) of the masking signal MS (i.e., the falling edge of the secondmirror pattern 80B).

[0073] The land/groove transition information detector 84 can furtherinclude a mask-triggering signal generator 110 for generating amask-triggering signal TM. The mask triggering signal generator 110responds to the confirmative signal CF from the second counter 106 andthe mirror pattern detecting signal MD from the mirror pattern detector100 and generates the mask triggering signal TM to be applied to themasking signal generator 108. The mask-triggering signal is a pulsemaintaining a first logic level (i.e., a high logic level) from thestarting point of the confirmative signal CF to the end point of thesecond mirror pattern 80B, as shown in FIG. 20. The masking signalgenerator 108 responds to the mask triggering signal TM and forces themasking signal MS to change from the specific logic level (i.e., thehigh logic level) to a second logic level (for example, a low logiclevel), at the end time (i.e., the falling edge) of the mask triggeringsignal TM.

[0074] As described above, when an optical disc, in which the same-phasewobbling area 24A and the different-phase wobbling area 24B are formedas shown in FIG. 3, is accessed, or when an optical disc, in which thesame-phase wobbling area 34A, the different-phase wobbling area 34B andthe pre-wobbling and post-wobbling areas 34C and 34D are formed as shownin FIG. 8, is accessed, the information recording/reproducing apparatusdetects the identification code, the recording clock and the rotationspeed information from the same-phase component in the wobbling signal Wand processes the different-phase wobbling component as errors.Accordingly, the information is recorded the information at all of thesame-phase and the difference-phase wobbling areas in the optical discas shown in FIG. 3 and FIG. 8, by the information recording/reproducingapparatus. Further, when an optical disc, in which the same-phasewobbling area 34A, the different-phase wobbling area 34B and thepre-wobbling and post-wobbling areas 34C and 34D are formed as shown inFIG. 8, is accessed, the information recording/reproducing apparatusperforms rapidly and accurately the recording and reproducing of theinformation on the basis of the synchronous patterns detected from eachof the pre-wobbling area 34C and the post-wobbling area 34D. As aresult, the optical discs in which land and groove tracks are wobbled asshown in FIG. 3 and FIG. 8, can be accessed by the conventionalinformation recording/reproducing apparatus. Furthermore, the opticaldiscs in which the wobbling areas as shown in FIG. 3 and FIG. 8 areformed in the land and groove signal tracks are changeablely used forthe existing optical discs in which the wobbling areas as shown in FIG.1 and FIG. 2 are formed therein.

[0075] As described above, in the recording medium according to thepresent invention, the same-phase wobbling area and the different-phasewobbling area are alternately arranged in each of the respective landand groove tracks, and the ID information of the address information andso on is preformatted on the same-phase wobbling area. In such recordingmedium, the information is recorded on all of the same-phase wobblingarea and the difference-phase wobbling area by the synchronous patternon the same-phase wobbling area so that the information is recorded inall of the land and groove signal tracks without a waste of therecordable area. Accordingly, the recording medium according to thepresent invention is capable of maximizing the recording capacity.

[0076] Also, since the pre-wobbling area and the post-wobbling areahaving the synchronous pattern are further provided, the recordingmedium according to the present invention can be rapidly and accuratelyaccessed.

[0077] Furthermore, in the optical disc of land/groove recording systemaccording to the present invention, the frame information indicating theland/groove cross portion is preformatted on a data area between thephysical address PID and the synchronous signal. On the other hand, theinformation, which is against to the bi-phase modulating regulation,indicating the land/groove cross portion is included in a synchronoussignal which is positioned at the front or the before of the starting orend portion of the land or groove track. Therefore, the optical disc ofland/groove recording system according to the present invention allowsthe land/groove cross portion to be identified. The opticalrecording/reproducing apparatus of present invention detects theland/groove transition information preformatted on the disc and controlsaccurately the tracking servo and etc. on the basis of the land/groovetransition information. As a result, The optical recording/reproducingapparatus can record and reproduce the information on the land andgroove tracks which are alternately formed on the optical disc.

[0078] In addition, the optical disc of land/groove recording systemaccording to the present invention has the land/groove transitioninformation preformatted between the starting positions of the land andgroove tracks and the end positions of the groove and land tracks toallow the land/groove cross portion (or line) to be accuratelyidentified. Accordingly, the optical disc of land/groove recordingsystem prevents noises from including in the radio frequency signal whenthe land/groove cross portion (or line) is accessed. The apparatus ofrecording/reproducing the optical disc of land/groove recording systemdetects the land/groove transition information preformatted on the discand controls accurately the servo. As a result, The apparatus ofrecording/reproducing the optical disc of land/groove recording systemcan detect accurately the radio frequency signal from the land/groovecross portion.

[0079] Although the present invention has been explained by theembodiments shown in the drawings described above, it should beunderstood to the ordinary skilled person in the art that the inventionis not limited to the embodiments, but rather than that various changesor modifications thereof are possible without departing from the spiritof the invention. For example, although optical discs has been used inthe embodiments of the present invention, it should be understood to theordinary skilled person in the art that the present invention isapplicable to an optical magnetic disc. Accordingly, the scope of theinvention shall be determined only by the appended claims and theirequivalents.

What is claimed is:
 1. A recording medium having a signal track wobbledin a predetermined frequency, the signal track comprising: firstwobbling area having a readable identified information; second wobblingarea having a non-readable identified information and alternating withthe first wobbling area.
 2. The recording medium as claimed in claim 1 ,wherein the first wobbling area is formed by wobbling both sides of thesignal track in same phase, and the second wobbling area is formed byboth side of the signal track in different phase.
 3. The recordingmedium as claimed in claim 1 , wherein the first wobbling area and thesecond wobbling area are alternatively arranged in width direction ofthe signal track.
 4. The recording medium as claimed in claim 1 ,wherein the first wobbling area having the readable identifiedinformation is positioned the signal track adjacent to the secondwobbling area.
 5. The recording medium as claimed in claim 1 , whereinthe first wobbling area and the second wobbling area adjacent to eachother forms an information record unit.
 6. The recording medium asclaimed in claim 5 , wherein the second wobbling area records aninformation in accordance with the readable identified informationpreformatted on the first wobbling area.
 7. The recording medium asclaimed in claim 1 , wherein the signal track includes: a land track;and a groove track adjacent to the land track.
 8. The recording mediumas claimed in claim 7 , wherein the recording medium is formed in discshape, and the land and groove track is formed from inner circumferenceto outer circumference in parallel.
 9. The recording medium as claimedin claim 7 , wherein the recording medium is formed in disc shape, andthe land and groove track is alternatively formed by one turn.
 10. Therecording medium as claimed in claim 1 , wherein the signal trackfurther comprises a synchronous pattern preformatted between the firstand second wobbling areas.
 11. The recording medium as claimed in claim10 , wherein the synchronous pattern includes: first synchronous patternbeing positioned between the start point of the first wobbling area andthe end point of the second wobbling area; and second synchronouspattern being positioned between the start point of the second wobblingarea and the end point of the first wobbling area.
 12. The recordingmedium as claimed in claim 11 , wherein the first and second synchronouspattern have logical values in complementary relationship, respectively.13. The recording medium as claimed in claim 11 , wherein the first andsecond synchronous pattern are alternatively arranged in width directionof the signal track.
 14. The recording medium as claimed in claim 2 ,wherein the different types of wobbling signals have the same length.15. An information recording/reproducing apparatus of performing arecording/reproducing of information for the recording medium as claimedin claim 1 , wherein the information recording/reproducing apparatusproceeds the recording/reproducing of information using the identifiedinformation preformatted on the first wobbling.
 16. The informationrecording/reproducing apparatus as claimed in claim 14 , wherein thefirst wobbling area and the second wobbling area adjacent to the firstwobbling area is treated as an information record unit.
 17. An opticaldisc comprising: a land track; a groove track alternated with the landtrack; and a land/groove transition information including a mirrorpattern.
 18. The optical disc as claimed in claim 17 , wherein theland/groove transition information further includes a transition datapattern.
 19. The optical disc as claimed in claim 18 , wherein theland/groove transition information is a data being against a bi-phasemodulating regulation and is preformatted on a synchronous signal areacorresponding to a position that the track changes from any one of theland and groove tracks to another track.
 20. The optical disc as claimedin claim 18 , wherein the transition data pattern includes a pluralityof spacers and recording marks each having the size of 4T.
 21. Anapparatus for recording and reproducing an information on an opticaldisc having a land and groove tracks alternated in a predetermined trackperiod, comprising: means for detecting a land/groove transitioninformation on the optical disc, the land/groove transition informationindicating a land/groove cross position between any one of the land andgroove tracks and the another track; and a servo motor unit, responsiveto the land/groove transition information, for controlling a servo motorand for inverting a tracking error signal in the polarity, the trackingerror signal forcing a light beam on the optical disc to be traced to acenter line of the land and groove tracks.
 22. The apparatus as claimedin claim 21 , wherein the land/groove transition information is a databeing against a bi-phase modulating regulation and is preformatted on asynchronous signal area corresponding to the land/groove cross position.23. The apparatus as claimed in claim 21 , wherein the land/groovetransition detecting means includes: a mirror pattern detector fordetecting first and second mirror patterns arranged on both ends of theland/groove transition information to generate first and second mirrorpattern detecting signals; a masking signal generator for generating amasking signal having a first logic value responsive to the first mirrorpattern detecting signal and a second logic value responsive to thesecond mirror pattern detecting signal; a signal detector, responsive tothe first logic value of the masking signal, for detecting thepredetermined number of spacers and recording marks arranged between thefirst and second mirror patterns to generate pulses; a first counter,responsive to the first mirror pattern detecting signal and the maskingsignal, for counting the pulses from the signal detector to generate aswitching signal when the counted number of the pulses is a firstpredetermined number; and a second counter, responsive to the switchingsignal and the masking signal, for counting the pulses from the signaldetector to generate a confirmative signal when the counted number ofthe pulses is a second predetermined number.
 24. The apparatus asclaimed in claim 23 , wherein the servo motor unit forces the polarityof the tracking error signal to be inverted and the control status ofthe servo motor to change when the switching signal is received, and thepolarity of the tracking error signal and the control status of theservo motor to be selectively returned to an original status whether theconfirmative signal is received or not.
 25. The apparatus as claimed inclaim 23 , further comprising a triggering signal generator forgenerating a mask-triggering signal having a first logic valueresponsive to the confirmative signal and a second logic valueresponsive to the second mirror pattern signal.
 26. The apparatus asclaimed in claim 25 , wherein the masking signal changes from the firstlogic value to the second logic value when the mask-triggering signal isswitched from the first logic value to the second logic value.